1. Field of the Invention:
This invention relates to a body fluid-absorbing article using a specific absorbent member containing an absorbent polymer. More particularly, it relates to a body fluid-absorbing article possessing notably improved absorption properties such that even after absorption of body fluid, the absorbed body fluid is stably retained long therein without suffering leakage sideways.
2. Description of the Prior Art:
As absorbent members for such body fluid-absorbing articles as disposable diapers, sanitary napkins, and sweat-absorbing pads, the products obtained by combining such fibrous materials as cotton, pulp, and paper with absorbent polymers as disclosed in U.S. Pat. Nos. 3,669,103; 3,670,731; 4,102,340; 4,364,992; and 4,610,678 have been in popular use in recent years. From the standpoint of ensuring ease of carriage and comfort of wear, these absorbent articles are tending toward reduction of size. In the circumstances, absorbent articles which incorporate therein absorbent polymers in increasingly large proportions have been appearing in increasing volumes in the market.
In the conventional body fluid-absorbing articles which use absorbent members incorporating therein absorbent polymers, however, no due attention has been paid to the prevention of absorbent polymers used therein from being deteriorated and decomposed by the absorbed body fluid, though numerous uniquely devised constructions have been proposed for use in such body fluid-absorbing articles as disclosed in the aforementioned patent publications. When they absorb such body fluids as urine, menstrual blood, and sweat, the swelled gel of the absorbent polymer in the absorbent member gradually undergoes deterioration and decomposition even to a point where the absorbent member is no longer able to retain the absorbed body fluid stably and present sideways leakage of the body fluid, often with the result that the leaking body fluid will smear bedclothes and clothing.
As means of preventing the absorbent polymer from being deteriorated and decomposed by the absorbed body fluid, U.S. Patent No. 4,666,975, for example, has proposed a method for improving the stability of the swelled gel by allowing the particles of the absorbent polymer to assume an increased cross-linking density in the surface region thereof. The absorbent polymer obtained by this method, however, suffers inevitably from a decrease in the capacity thereof for holding the absorbed body fluid. Thus, the absorbent polymer has found utility in absorbent members for body fluid-absorbing articles only with difficulty.
As described above, the conventional body fluid-absorbing articles have posed a problem in the sense that the ability of the absorbent member to retain the absorbed body fluid is degraded with elapse of time even to a point where the sideways leakage of the absorbed body fluid will become inevitable. In the circumstances, the desirability of developing a body fluid-absorbing article . of improved absorption properties incorporating therein an absorbent polymer-containing absorbent member excellent in ability to retain the absorbed body fluid stably for a long time has been finding growing recognition.
An object of the present invention, therefore, is to provide a novel body fluid-absorbing article.
Another object of this invention is to provide a body fluid-absorbing article of improved absorption properties incorporating therein an absorbent member excellent in ability to retain the absorbed body fluid for a long time.